The present invention relates generally to a key-activated security device for an automotive vehicle and more specifically to a method and apparatus controlling the operation of the security system.
Several security systems use two lines of defense. A first line of defense is a cut key that is used to operate the system if the cut of the key matches the lock in which it is inserted. A second line of defense is housing electronic circuitry on the key that has a unique identification code. When a properly cut key is inserted into the lock, a security device interrogates the electronic circuitry for its security code. If the security code is the proper lock operator, the engine is allowed to start.
The time between the interrogation of the electronic circuitry and the starting of engine may vary depending on such factors as humidity and temperature. One problem with prior security device is that if the engine starts a long duration after turning the key in the lock, operators perceive a problem.
Another drawback with prior security devices is that if the operator's vehicle does not start, no indication of the cause of the problem is indicated. In other words, the operator does not know whether the car is not starting because of a defective security system or whether the car is not starting because of a defect in the engine or associated components.
Related application 08/270,979 uses a transponder having a key code that is coupled to a theft control module through an antenna. The theft control module allows the vehicle to start before checking for a valid transponder code in the key to eliminate the delay between interrogating the key in the ignition and starting the engine. One drawback to the system is that the vehicle may be moved before the system is disabled if a valid key code is not found.